Method for fabricating optical information storage medium

Abstract

In forming steps of a recording layer or a dielectric layer of a phase change type optical disk by sputtering, a discharge gas which includes at least one of Kr gas and Xe gas is used. Alternatively, at least one of Ar gas and N 2 gas may be further added to the discharge gas. Forming the recording layer or the dielectric layer of the phase change type optical disk in these discharge gases enables preventing of the introduction of the discharge gas into each layer during the forming steps. As a result, the void generation and growth in the recording layer is suppressed. Consequently, the deterioration of the cycle life characteristics due to repeated overwrite operations can be restrained. Therefore, high reliability and long life of the phase change type optical disk is attained.

What is claimed is: 
     
       1. A method for fabricating an optical information storage medium comprising on a substrate, a recording layer which shows reversible phase change between an amorphous phase and a crystal phase, said method comprising the step of forming said recording layer by sputtering in a discharge gas, said discharge gas including at least one of Xe gas and Kr gas.   
     
     
       2. A method according to claim 1, wherein said discharge gas further includes Ar gas. 
     
     
       3. A method according to claim 1, wherein said discharge gas further includes N 2  gas. 
     
     
       4. A method according to claim 3, wherein said discharge gas includes Kr gas and N 2  gas, a partial pressure ratio of said N 2  gas to a total pressure of said discharge gas being in a range from 0.25% to 10%. 
     
     
       5. A method according to claim 3, wherein said discharge gas includes Xe gas and N 2  gas, a partial pressure ratio of said N 2  gas to a total pressure of said discharge gas being in a range from 0.25% to 5%. 
     
     
       6. A method according to claim 1, wherein said recording layer has a main component selected from the group consisting of SbTe, GeSbTe, GeSbTeSe, GeSbTePd, TeGeSnAu, AgSbTe, GeTe, GaSb, InSe, InSb, InSbTe, InSbSe and InSbTeAg. 
     
     
       7. A method for fabricating an optical information storage medium comprising on a substrate, a first dielectric layer formed on said substrate, a recording layer which shows reversible phase change between an amorphous phase and a crystal phase, said recording layer formed on said first dielectric layer, and a second dielectric layer formed on said recording layer, said method comprising the step of forming at least one of said first dielectric layer, said recording layer and said second dielectric layer by sputtering in a discharge gas, said discharge gas including at least one of Xe gas and Kr gas.   
     
     
       8. A method according to claim 7, wherein said method further comprises the step of forming a reflecting layer on said second dielectric layer. 
     
     
       9. A method according to claim 7, wherein said discharge gas further includes Ar gas. 
     
     
       10. A method according to claim 7, wherein said discharge gas further includes N 2  gas. 
     
     
       11. A method according to claim 10, wherein a partial pressure ratio of said N 2  to a total pressure of said discharge gas is in a range from 0.1% to 10%. 
     
     
       12. A method according to claim 7, wherein said recording layer has a main component selected from the group consisting of SbTe, GeSbTe, GeSbTeSe, GeSbTePd, TeGeSnAu, AgSbTe, GeTe, GaSb, InSe, InSb, InSbTe, InSbSe and InSbTeAg. 
     
     
       13. A method according to claim 7, wherein said first dielectric layer and said second dielectric layer are made of at least one material selected from the group consisting of SiO 2 , SiO, TiO 2 , MgO, Ta 2  O 5 , Al 2  O 3 , GeO 2 , Si 3  N 4 , BN, AlN, SiC, ZnS, ZnSe, ZnTe and PbS. 
     
     
       14. A method according to claim 7, wherein said first dielectric layer, said recording layer and said second dielectric layer except said at least one layer are formed by sputtering in Ar gas.